"Theodore Ts'o" tytso@mit.edu writes:
On Mon, Jul 17, 2023 at 08:04:54PM +0530, Ritesh Harjani wrote:
These can basically trigger in extremely low memory space and only when such ranges exist in the PA rbtree. Hence, I guess it is a little hard to tigger race.
Ritesh, thanks for looking into this!
Naresh, how easy is it for you to trigger the BUG when using LTP? I did two xfstests runs using "gce-xfstests -c ext2/default -g auto", one on the ext4 dev branch, and one on linux-next 20230717, and I wasn't able to trigger the BUG.
If you can trivially trigger it using LTP (perhaps with a low memory configuration in your test setup?), that would be useful to know.
Hi Ted,
Hi Ted, Ritesh, all,
Sorry for wrong choice of words. By low memory space I meant low disk space i.e. ENOSPC test (fs_fill). I reproduced it like this -
root@ubuntu:/opt/ltp# while [ 1 ]; do ./runltp -s fs_fill; sleep 1; done
Late, but better than never: LTP C tests can be run without any wrapper. e.g. to reproduce the bug triggered by fs_fill, you can just:
git clone https://github.com/linux-test-project/ltp.git && cd ltp ./ci/your-distro.sh # optionally install the dependencies make autotools ./configure cd testcases/kernel/fs/fs_fill/ make -j`nproc` while true; do ./fs_fill; sleep 1; done
NOTE: runltp is 1) deprecated, replaced by runltp-ng [1] 2) again, there is no need to use this shell wrapper to run a single C binary
Kind regards, Petr
[1] https://github.com/linux-test-project/runltp-ng
For me it took around ~1-2 hours for it to reproduce when I tried again. I am hoping if we run generic/269 (fsstress ENOSPC) in a while loop like this maybe it can hit this bug. But I didn't give it a shot.
-ritesh